Dipper-tooth point with hollow surfaces



W. S. McKEE.

DIPPER TOOTH POINT WITH HOLLOW SURFACES.

APPLICATION FILED OCT. 23. l9l9.

1,427,610. Patented Aug 29, 1922.

on-ice.

WALTER S. MORE E, OI CHICAGO, ILLINOIS.

DIPPER-TOOTH I OINT WITH HOLLOW SURFACES.

Specification of Letters Patent.

Patented Aug. 29, 1922.

Application filed October 23, 1919. Serial No. 332,658.

Illinois, have invented certain new and usewith ful Illnlprovements in Dipper-Tooth Points ollow Surfaces, of which the followin is a specification.

1 specification.

My invention relates to teeth designed for use with the dippers or buckets of excavating, dredging, digging and similar machines, and particularly (although not exclusively) to the kind of teeth in which a permanent supporting member or base is provided integral with a dipper front, such for instance, as that disclosed in Patent No. 1,126,319 to Vanderhoef and Johnson, and to the ends of which bases detachable dipper tooth points may be secured, so that when the points become dull or Worn out in service the points may be reversed to present new cutting edges or replaced by new points without having todiscard the base portion of the tooth, or the dippenfront, if used with the latter.

The main object of my invention is to provide a detachable dipper tooth point of the reversible type made in such a manner as to prolong the effectiveness of the cutting ed es and to shape the same whereby the polnts may be more easily forced into the material being dug. Such construction requires less horse power than would be the case if the usual points having straight upper and lower surfaces were used.

Another object of my invention is to improve dipper teeth points for successful commercial use.

A further object is to provide points for dipper teeth which will wear longer in service and give better digging results than the present type.

' Other objects will be apparent from the I carry out, my invention in preferred form by hollowing out the top and bottom of the'point. By hollowing out of the top and .bottom I mean that a straight line drawn from the center line of .the point to the widest part of the point in side elevation is not coincident with the upper and lower surfaces of the point, but that the lines defining the point in side elevation diverge below the above mentioned line to a point not far from the front of the jaws and then diverge more rapidly to the highest point of the tooth point. In other words, the thickness of the point has a divergence less acute for a certain portion of its length than in other portions. By referring to the drawings, the object of my invention willbe better understood, and wherein: p j V Figure 1 shows in side elevation a dipper point made in accordance with the preferred embodiment of my invention.

Fig. 2 is a bottom plan view of the point of Fig. 1, and

Fig. 3 is an end view looking from the right hand side of Fig. 1.

As is usual in reversible dipper points, there are provided two integral rearwardly extending jaws 5 and 6, made to engage the ends of the base portions of the teeth, or where the base portions are cast integrally with the dipper front to engage said integral portions. In the drawing the jaws are shown as substantially parallel for a portion of their length and then converge to a fillet-7. While the jaws are shown as being parallel for a portion of their length it is not essential, as many points are made having-the jaws divergent the full length thereof. The only requisite of a reversible point is that it be symmetrical with respect to the center line through the point thereof. It is desirable to insert a vertical web 8 just back of the fillet 7 for engagement with a vertically-disposed slot in the base portion of movement of the points. The jaws 5 and 6 are provided with suitable apertures 16 through which bolts, rivets or other attachmg means may pass to fasten the points to the tooth bases. X

The solid portion of the tooth comprises in' the form shown, the digging point shown at 9, which is a chisel point and may be sharpened by forging or hammering. The solid portion of the point extends back to the fillet 7 where the jaws begin. It will be noted that ifa line 10 be drawn from the center line 11 to touch thepoint 9 and the widest point'12 of the dipper tooth point, the upper surface 13 of the solid portion of an additional means for preventing sidewise the point will lie below said line forming a hollow, as I term it. The surfaces defining the top and bottom portion baclc of the chisel point 9 may be indicated by reference characters 13 and 13 the latter meeting the line 10 at point 12. A similar line 10 is drawn along the under side of the tooth as indicated to show the hollow portion formed in the under side of the tooth. It is usual in the manufacture of these points to forge .the cutting edge, which operation may be utilized to bring the point to the shape shown in Fig. 1, that is, to the ultimate form desired. 7

Experience has shown that the cutting edges of points embodying my invention remain sharper a much longer time than is true of the present type of tooth. All the wear on such a point is along the back, so that a point made in accordance with this invention does not necessarily wear faster than the present type as the wear at the back is comparatively slight.

In manufacture the tooth is made following standard foundry practice for such articles, and when such articles are made of manganese steel, which I prefer to employ, the necessary heat treatment is carried out. As the heat treatment of manganese castings is an important step in their manufacture the castings must be made with the purpose in view of permitting maximum efficiency in heat treatment. relationship exists between the thickness of the metal and the amount that the heat treatment affects such castings, and such relationship must of course be maintained in manufacturing dipper points embodying my invention.

While I have described more or less precisely the details of construction of my invention, I-do not wish to be understood as limiting myself thereto, as I contemplate changes in form and the proportion of parts It has been found that a and the substitution of equiv'alents as air to the central plane from that point to the wider portion of the tooth.

2. A dipper tooth poirit comprising a digging portion merging with jaws for securing the point to a bucket, the top and bottom surfaces of the point diverging at narrow angles to the central plane of the tooth from the front end to a point adjacent to the junction with the jaws, and diverging at greater angles to the central plane from that point rearwardly 3. A point member for dred e buckets and the like formed with a forwar portion hav-.-

ing top and bottom surfaces at an acute angle of divergence to an intermediate point, and a greater angle of divergence from beyond that point to the widest part of the tooth.

4. A-dipper tooth point for dredge buckets and the like having its forward portion 'formed with an included angle approximately one-half the included angle of the rearward portion which extends towards the widest portion of the point.

5. A tooth point for excavating dippers formed of cast metal, the forward or digging portion having an acute included angle, and the rearward portion having an included angle approximately twice that of the forward or digging portion.

Signed at Chicago, Illinois, this 17th day of October, 1919.

. WALTER S. MoKEE. 

